Liquid crystal display devices, which can reduce power requirements in driving, are widely used as not only portable devices but also stationary video display devices. In the liquid crystal display devices, digital data corresponding to grayscale of each pixel in a display panel is supplied to a data signal line drive circuit. The data signal line drive circuit applies to a data signal line a potential of an analogue signal corresponding to a value of the digital data, thereby controlling luminance of each pixel.
The liquid crystal display devices generally adopt hold display in which writing is performed once during one frame period (i.e. all gate lines are turned on only once during one frame period), and a written state is maintained until a next frame comes. However, such a hold display gives rise to the problem that blurring in a moving image is likely to occur. In order to solve the problem, there has been proposed a method in which one frame is divided so that a potential of a signal is written to each pixel more than once during one frame period (time-division driving, see Patent documents 1 and 2, for example). In the time-division driving, one frame period is divided into sub-frames at a predetermined ratio (e.g. 1:1) and display luminance of one frame is expressed by a temporal sum of display luminances of the respective sub-frames.
[Patent Document 1]
Japanese Unexamined Patent Publication No. 68221/1993 (Tokukaihei 5-68221; Mar. 19, 1993)
[Patent Document 2]
Japanese Unexamined Patent Publication No. 296841/2001 (Tokukai 2001-296841; Oct. 26, 2001)